Title

Development of Modified Membranes for High-Performance Zinc-Bromine Redox Flow Batteries

Alternative Title

고성능 아연-브롬 레독스 흐름 전지를 위한 개질막 개발

DGIST Authors

Sifathul Jannah ; Sangaraju Shanmugam ; Dong Hae Ho

Advisor

상가라쥬 샨무감

Co-Advisor(s)

Dong Hae Ho

Issued Date

2026

Awarded Date

2026-08-01

Type

Thesis

Description

zinc–bromine redox flow batteries, SPEEK, polybenzimidazole, Nafion, UiO-66 mixed-matrix membrane, casting solvent, bromine crossover, membrane stability, zinc dendrite

Table Of Contents

Ⅰ. INTRODUCTION 1
1.1 Theoretical Background 1
1.2 Redox Flow Batteries （RFBs） 3
1.3 Challenges in Zn-Br RFBs 6
1.3.1 Polybromides Crossover 6
1.3.2 Zn Dendrite Formation 9
1.4 Strategies for the challenges of Zn-Br2 RFBs 12
1.4.1 Sulfonated Polymer-Based Blend Membrane 12
1.4.2 Modification of existing Nafion membrane 14
1.5 Motivation and Goal of This Thesis 15
1.5.1 Sulfonated Polymer-Based Blend Membrane 16
1.5.2 Modification of Existing Nafion Membrane 16
Ⅱ. EXPERIMENTS 18
2.1 Materials 18
2.2 Preparation of sulfonated poly（ether ether） ketone 19
2.3 Preparation of UiO-66-NH2-SO3H 20
2.4 Membrane Preparation 20
2.4.1 SPK/PBI blend membrane 20
2.4.2 Nafion/U-AS composite membrane 21
2.5 Characterization 21
2.6 Water Uptake, Swelling Degree 22
2.7 Ion Conductivity Measurement 23
2.8 Bromine Permeability Measurement 23
2.9 Chemical Stability Evaluation 24
2.10 Measurements of Zn-Br2 RFB Performance 25
Ⅲ. Stabilizing Highly Sulfonated Poly（ether ether ketone） Membranes with
Polybenzimidazole for Zinc-Bromine Redox Flow Batteries 26
3.1 Introduction 26
3.2 Results and Discussion 28
3.2.1 Characterization 28
3.2.2 Mechanical and Thermal Stability 33
3.2.3 Ionic Conductivity and Br2 Permeability 34
3.2.4 Chemical Stability of Membrane 37
3.3 Electrochemical Performance in ZBRFBs 40
3.3.1 Rate Capability and Short-Term Cycling 40
3.3.2 Long-Term Cycling Stability 44
3.4 Post-Mortem Analysis 46
3.4.1 Chemical Analysis 46
3.4.2 Morphological Analysis 48
3.5 Summary 51
Ⅳ. Impact of Solvent-Dependent Nafion Morphology on the Performance of UiO-66-NH2-
SO3H Mixed-Matrix Membranes in Zinc-Bromine Redox Flow Batteries 53
4.1 Introduction 53
4.2 Results and Discussion 56
4.2.1 Characterization of UiO-66-NH₂-SO₃H （U-AS） and Recast Nafion Membranes 56
4.2.2 Hansen Solubility Parameter Analysis 59
4.2.3 Physicochemical and Transport Properties of Nf/U-AS Composite Membranes 61
4.2.4 Chemical Stability of Membranes 64
4.2.5 Zn-Br2 RFB Performance 66
4.3 Post-mortem Analysis 76
4.3.1 Morphological Analysis of Membranes and Electrodes 76
4.4 Summary 79
Ⅴ. CONCLUSION 82
References 85
요 약 문 91

URI

https://scholar.dgist.ac.kr/handle/20.500.11750/60793
http://dgist.dcollection.net/common/orgView/200001012331

DOI

10.22677/THESIS.200001012331

Degree

Master

Department

Department of Energy Science and Engineering

Publisher

DGIST

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